Well repair



Jan. 24, 1950 R. H. SMITH WELL REPAIR Filed Dec. l2, 1945 Unullllllllllllnlllllllllllllln ZWM \h\lllllllll\llllhillln A TTORNEYS Patented Jan. 24, 1950 WELL REPAIR Ralph H. Smith, Houston, Tex., assigner to The Dow Chemical Company, a corporation of Dela- Ware ' Application December 12, 1945, Serial No. 634,513

(Cl. 16S-22) l 8 Claims. 1

The invention relates to methods of repairing well structures. It more particularly concerns a method of making repairs to a well liner or casing.

In the construction of deep wells, it is usual to case the bore with pipe which extends from the top of the well to a rock or other dense consolidated formation not requiring support to prevent caving or sloughing. An inner casing or liner is then run into the well through the cased bore to the production stratum. Opposite the production stratum, the casing or liner is usually perforated to permit passage of oil into the well. These inner casings or liners sometimes become damaged, the damage being confined, oftentimes, to only a small portion leaving most of the liner intact. Such damage may result from the application of an excessive longitudinal tension or compression stress, as in pulling a liner-for example, which may cause the liner to part at some point in the well. Liners are sometimes damaged in treating Wells with chemical solutions introduced under pressure through the liner as when excessive treating pressures are used which causes the liner to burst. Liners or casings thus damaged present a diflicult problem of repair.

Accordingly, it is the principal object of the invention to provide a simple and effective method of making repairs to casings or liners in a deep well.

Other objects and advantages will appear from the accompanying drawing and following description setting forth a preferred mode of carrying out the invention, such mode illustrating, however. but one of the various ways in which the principle of the invention may be practiced.

In the said drawing:

Fig. 1 is a longitudinal section through a portion of a well bore partly cased and having a liner therein with a break below the casing;

Fig. 2 is a similar View of the well with the portion of the liner above the break removed, and showing the well prepared forthe repair operation;

Fig. 3 is a similar view of the well showing initial stages of making a liner repair according to the invention;

Fig. 4 is a similar view of the well showing subsequent stages in the linerrepair operation;

Fig. 5 is a similar view of the well showingl a completed repair. v

As shown in the drawing, wherein like numerals refer to like parts in the several gures,

the upper portion of the well bore I is cased` with pipe 2 which extends above the ground level 3, the space between the pipe and the well bore being lled with cement 4. The casing is equipped with a head 5 and a pipe connection 6 having a valve 1 for controlling the ow of fluid into or out of the casing. Passing through the casing head 5 into the well is a liner 8, which is shown as having'been damaged, the damage being indicated by a parting at 9 disconnecting the upper portion I0 from the lower portion II.

In Fig. 2, the well has been put under hydrostatic control by a column of drilling mud I2 and the upper portion of the liner string above the break 9 has been removed.

In Fig. 3, an upper portion I3 of liner is shown in the well, the liner being provided with a re movable head 22, and a pipe connection 23 with a valve 24. The lower end I4 of the liner is joined by a collar I5 to a cylindrical member I6, larger than the liner, the big end I1 of which is adapted to slip over the upstanding end II of the lower portion of the original liner.

1n carrying out a repair operation, according to the invention, the portion I0 of the liner above the break 9 is removed from the well. This may be accomplished in the usual way, as by withdrawal through the casing head. In order to retain hydrostatic control of the well, it may be filled, if necessary, with drilling mud I2 or other suitable uid which does not readily seep into the surrounding earth, as shown in Fig.'2.

The cylindrical member I6 is secured to the lower end I4 of a liner string by means of a collar I5 (the withdrawn portion of the liner being used if desired), the cylindrical member beingV adapted to slip over the upstanding end II of the lower portion of the liner in the well, and the assembly is lowered into the well until the cylindrical member receives the upstanding end of the liner. A cylindrical member may be used which leaves annular spaces I8 and I9 between the cylindrical member I6, the liner II in the well hole and the well hole I, respectively.

A fluid sealing compound which adheres to Aand makes a tight seal with the surface of the metal pipe when set is then introduced into .the annular spaces I8 and I9 in amount sufficient to ll the bore 'from about the lower end 20 of the cylindrical member to the upper end 2I thereof and the annular space I8. The tightness of the seal produced between the inside of the cylindrical member and the'outside of the upper end of the lower portion of the liner depends largely upon the choice of sealing material. I have found that by using partially condensed mixtures of phenol and formaldehyde or other resin-forming liquids capable of transformation into solid resins without significant contraction in volume are suitable. An example of a resin-forming liquid is the following:

Mix 40 parts vby weight of phenol with V50 parts by weight of an aqueous solution of formaldehyde containing 37 per cent by volume of formaldehyde and add thereto 1.35 parts by weight of sodium hydroxide. The resultingfsolution is then heated for 6 hours at a temperature cf between 75 to 80'-C.:and .becomes a clear amber liquid. This clear Vliquid is then pared is introduced into fthe well while-in`the pumpable state.

Spotting the sealing compound at the -desired places may be accomplished-by openingthe valve 'I and introducing yiirst a quantity of water, Vif desired. into'the upper end of ythe liner I'Sthrough valve 2A so as to ush off mud fromthersurface of the pipe and then a travelling plug,-such v-as a conventional cementing plug, making a=sliding sealing 'ilt with-the insideof thelinen'the liner head 22 being removed to admit the plugand then'replaced. The requisite volume cfliiuid sealing compound, prepared -Ias -aboveor otherwise, is then introduced into vvthelinerbehind therst plug `and after the charge of sealing -compound is vin the liner `a `second cementing plug-fis inserted in the'liner in'thesamemannercas the rst'plug just behindtlie'sealing compound. `A pressuringliquid, such as water, is Afnext'introduced behind the second'plug =so:as`to'forcelthe two-plugs and thecharge of sealing compound contained between v"them down the liner to `the cylindrical member while a, `corresponding volume of mud fiuid, thereby displaced, is `permitted 'to escape from the'valve 'I asshown in YFig. 3. In

this view, the spotting operation isfshown asihavn' ing'reached'the-stage where the rst plugi25lhas come to rest against .the-upstanding end25 o'f the liner I I and the charge of sealing fluid 221, which is about to enterlthe annularfspaceil', is separated from the pressuring fluid 28`fby 1the second plug 29. Y

The introduction of pressuring fluid'isrcontinued until the :second plug A29 comes rto 'rest on therst plugt25,.assshown.in Fig.`4, and the sealing compound is displaced into theannular spaces `I8 and i9 between thelevels '30 and'3l. Passage of the sealing compoundinto the'lower portion of the well belowtheicylindrical memberf is .prevented by v the iiuid (mud) :column 32 Ithereinfas shown. A corresponding volume of i'luid'escapes through valve I lasthesealingiuid is :displaced intotheaforesaid:spaces,-"andawhenfthe'displacementis complete, the valve'lis 'closed v'and the well maintained underpressure, if necessaryfto keep the sealingcompound-in place'whileitfsets I toa solidmass.

After Athe sealing compoundhas vsetfthe `Vhead '22 yis removed from the topof ithe liner andthe :bore clearedby `drilling a rpassageifrom' thezupper portion 1 I 3 to :the lower lportion l I o'f .theflinen :some instances the useiof either the upper or the lower, or both, plugs may be dispensed with, as

rwhen the distance to be travelled by the sealing `compound is relatively short, i. e. when the cylindrical member is not far below ground, or when some mixing of the sealing compound with the fluid displaced byittand with the pressuring iiuid vis not objectionable.

In dispensing with both plugs, the mode of operation is as follows: After lling; if necessary, the liner and casing with some liquid,.such as oil, water, or drilling mud, as previously described, the requisite quantity of sealing compound may be-introduced into the liner lstring 1I 3 and then thepressuring fluid which is introduced behind-the sealing compound. The introduction-of pressuring'fluid is continued while venting the casing through valve I until a sufficient volume has beenintro'duced to ll the liner string 'to the top of 'the cylindrical member I6, thereby moving'the 'sealing compound into the cylindrical member and the annular space I9 around the overshot. The sealing compound is then maintained in position until set, as by closing the casing and the liner string valves 'I and 24, respectively, After the sealing compound has had time to hardengthehead 22 is removed and the liner string cleared, if necessary, ofsetsealingcompound, by boring a passage from the upper to the lower section of the string, leavingan annulus I8'ofset sealing compound between the outside of theupstanding 'end II of the liner and the inside of the cylindrical member. In carrying `outthe process vwith'but one plug, the

`operation is the'same'as that just described with- `outplugs, except' that one plug is introduced into the liner lstring either ahead of or behind the charge lof `sealing compound.

In its' broader aspects, then, lthe invention contemplates the Arepair 'of a 'casing 4or liner either with or without the use of travelling plugs to separate the sealing compound from the fluid above'andbelow it "as the sealing compoundis moved into positionin thewell.

In actual use of this method in a deep well in making-a repair-of a'51/2 inch liner,'which split ata depthfof 2750'feet dueito the application of an .excessive pressure (4200 p.'s. i.) a strong presvsure `tight seal was obtained which withstood a waterpressure test Vof I900,p..s..i. between the inside'and outside of the liner at the depth of the repair.

I claim: Y

LThe method of repairing albreak in -a liner in a deep well which comprises Ywithdrawing from the well the portion ofthe liner above. the break so asto .leave `the remainder ofthe liner with severed end upstanding in the well, attaching ,a cylindrical member larger than the liner tolthe lower endfofalineristring,.said cylindrical memberbeing `-adapted v-to slip `over the'upstanding end of the liner in the well, ,loweringithe said liner Ystring 'with the attached lcylindrical member'intotheswell soas to place the 'cylindrical member over the upstanding `end of lthe liner, .introducing into the annular spaces between the cylindrical member, the `liner in the Vweiland the well :hole =a vfluid sealinglcompound vcapaltile offsetting 'to `-a Dsolid, 'and' after *the sealing 'compound has set forming an axial passage from the upper to the lower portion of the liner.

2. The method of repairing a break in a liner in a deep well which comprises withdrawing from the well the portion of the liner above the break so as to leave the remainder of the liner with severed end upstandng in the well, vattaching a cylindrical member larger than the liner to the lower end of a liner string, said cylindrical member being adapted to slip over the upstanding end of the liner in the well, lowering the said liner string with the attached cylindrical member into the well so as to place the cylindrical member over the upstanding end of the liner, introducing into the liner string in the order named a quantity oi" a iluid sealing compound in amount at least suflicient to i'lll the Well hole for a depth equal to the length of the cylindrical member and then a pressuring liquid, continuing the introduction of the pressuring liquid until an amount has been introduced suilicient to ll the liner to the top of the cylindrical member, thereby displacing the sealing compound from the liner string above the cylindrical member into the annular spaces between the cylindrical member, the liner in the well and the well hole, permitting the sealing compound to set in situ so as to form a seal between the cylindrical member and the upstanding end of the liner inthe well, and after the sealing compound has set forming an axial passage from the upper to the lower portion of the liner.

3. The method of repairing a break in a liner in a deep well which comprises withdrawing from the well the portion of the liner above the break so as to leave the remainder of the liner with severed end upstanding in the well, attaching a cylindrical member larger than the liner to the lower end of a liner string, said cylindrical member being adapted to slip over the upstanding end of the liner in the well, lowering the said liner string with the attached cylindrical member into the well so as to place the cylindrical member over the upstanding end of the liner, introducing into the liner string in the order named a travelling plug, a quantity of a fluid sealing compound in amount at least suilicient to fill the well hole for a depth equal to the length of the cylindrical member, and a pressuring fluid, continuing the introduction of the pressuring iluid until an amount has been introduced suicient to fill the liner to the top of the cylindrical member, thereby displacing the sealing compound from the liner string above the cylindrical member into the annular spaces between the cylindrical member, the liner in the well hole and the well hole permitting the sealing compound to set in situ so as to form a seal between the cylindrical member and the upstanding end of the liner in the well, and after the sealing compound has set forming an axial passage from the upper to the lower portion of the liner.

4. The method of repairing a break in a liner in a deep well which comprises withdrawing from the well the portion of the liner above the break so as to leave the remainder of the liner with severed end upstanding in the well, attaching a cylindrical member larger than the liner to the lower end of a liner string, said cylindrical member being adapted to slip over the upstanding end of the liner in the well, lowering the said liner string with the attached cylindrical member into the well so as to place the cylindrical member over the upstanding end of the liner, introducing into the liner string in the order named a quantity of a fluid sealing compound in amount at least suiiicient to lill the well hole for a depth equal to the length of the cylindrical member, a travelling plug, and a pressuring fluid, continuing the introduction of the pressuring iluid until an amount has been introduced suflicient to ll the liner to the top of the cylindrical member,

thereby displacing the sealing compound from the liner string above the cylindrical member into the annular spaces between the cylindrical member, the liner in the well hole and the well hole, permitting the sealing compound to set in situ so as to form a seal between the cylindrical member and the upstanding end of the liner in the well, and then making an axial passage from the upper to the lower portion of the liner.

5. The method of repairing a break in a liner in a deep well which comprises withdrawing from the well the portion of the liner above the break so as to leave the remainder of the liner with severed end upstanding in the well, attaching a cylindrical member larger than the liner to the lower end of a liner string, said cylindrical member being adapted to slip over the upstanding end of the liner in the well, lowering the said liner string with the attached cylindrical member into the well so as to place the cylindrical member over the upstanding end of the liner, introducing into the liner string in the order named a iirst travelling plug, av quantity of a fluid sealing compound in amount suilicient to fill the well hole for a depth at least equal to the length of the cylindrical member, a second travelling plug, and a pressuring liquid, continuing the introduction of pressuring liquid until the second travelling plug reaches the cylindrical member so as to displace the iiuid sealing compound from the liner string into the annular spaces between the cylindrical member, the liner in the well and the well hole, permitting the fluid sealing compound to set in situ so as to form a seal between the cylindrical member and the upstanding end of the liner in the well, and then making an axial pas-vv sage from the upper to the lower portion of the liner.

6. The method of repairing a break in a liner in a deep well which comprises withdrawing from the well the portion of the liner above the break so as to leave the remainder of the liner with severed end upstanding in the well, attaching a cylindrical member larger than the liner to the lower end of a liner string, said cylindrical member being adapted to slip over the upstanding end of the liner in the well, lowering the said liner string with the attached cylindrical member into the well so as to place the cylindrical member over the upstanding end of the liner, lling the well and liner with a drilling mud so as to render the well hydrostatically controllable, introducing into the liner string in the order named a quantity of water, a first travelling plug, a quantity of a uid sealing compound in amount suicient to iill the well hole for a depth at least equal to the length of the cylindrical member, a second travelling plug, and a pressuring liquid, continuing the introduction of pressuring liquid until the second travelling plug reaches the cylindrical member so as to displace the fluid sealing compound from the liner string into the annular spaces between the cylindrical member, the liner in the well hole and the well hole, permitting the iluid sealing compound to set in situ so as to form a seal between the cylindrical member and the upstanding end of the liner in the Wellfiandfithennmaking an "aiiial passage 'from thefupperf-toithe lowersportion of the liner.

"57."The method-of repairingalbreak in a liner in -fa-deep well 4iii/which comprises :withdrawing from thevwell'thefportionrof the linerabove the break so yas to"leaveftheremainder ofthe liner Withlseveredfend upstanding in the well, atv length vof the cylindrical mernber, a `second travelling plug, anda pressuring liquid, eontinuing ther-introduction Aof ,pressuring liquid until the second travelling plug reaches the cylindrical member so'as to displace the resin-forming liquid'from the liner string into the annular ,spaces between Vthe cylindrical member, the liner in thewelland the vwellv hole, permitting the resin- 'forming liquidto set in situl sov as'to form a seal Y between the cylindricalrmember and the upstandingendof Ithe linerv inthe welLand then makingwan'aXial/passageifrom the upper to the lower* portion of the liner.

v8.*Tlie* methody ofrepai'ring `a break `in a Vliner in Va deep Awell which comprises withdrawing from the well vtlfiejlrnortion ofthe liner abovethe break so-asv to leave"theremainder of the liner with severed end `npstan'ding in the well, kattaching -a cylindrical member larger than the liner tothe lower'en'd of aliner string, said cylindrical member'being adapted to slip 'over the upstanding'endof the liner in' the well, lowering the ysaid yliner =fstring1with fthe fattache'd cylindrical member intothewell so yas to place the cylindrical "rner-nber-foverV theT upstanding end Vof the liner, introducing intoE the' liner string' in the order named -a first travellingV plug, v aquantity of a resinformingliquid-capable of setting toa solid'resinin-amount suiiioient to ll the well hole-for a depthv at least equal to the length of the cylindrical member, aseeond travelling plug, and a'pressuring'liquid, continuing the introduction of pressuring liquid until the second travelling plug reaches the cylindrical member so Vas to displace tlfie resiniforming liquid from the linerv string into thev annular spaces between thehcylindrical member, the liner in the well hole and the `well hole,""permitting the resin-forming liquid toset in situso'as to'forma seal between thev cylindrical-member and the upstanding end ofthe linerinthewell, and then making an axial passagefromthe upper to the lowerv portion of the liner.

'RALPH H. SMITH.

REFERENCES CITED The following reerenCesare of record inthe file ofthis patent:

UNITED STATES" PATENTS Number Name Date 1,269,090 "Kistler June 11, 1918 "1,369,891 'Halliburton Mar..1,11921 1,404,353 vEllis ,-Jan. 24, 1922 1,567,109 Boynton Dee. ,29, 1925 2,164,266 Armentrout et al. June 27, 1939 V2,219,319 iIrons Oct. 29, 1940 2,312,862 Bermingham,. Jr. Mar. 2, v19413 2,372,461 Uren Mar.. 27, 1945 V2,447,629 .'Beissinger et.,al. Aug. 24, 1948 FOREIGN `PATENTS Number Country Date 6,507 Great Britain ,.1904 

